Fix uninitialized memory error Valgrind bots are barking about.

base/prefs/json_pref_store.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/prefs/json_pref_store.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/callback.h"
@@ skipping 160 matching lines @@
     scoped_ptr<PrefFilter> pref_filter)
     : path_(filename),
       alternate_path_(alternate_filename),
       sequenced_task_runner_(sequenced_task_runner),
       prefs_(new base::DictionaryValue()),
       read_only_(false),
       writer_(filename, sequenced_task_runner),
       pref_filter_(pref_filter.Pass()),
       initialized_(false),
       filtering_in_progress_(false),
+      pending_lossy_write_(false),
       read_error_(PREF_READ_ERROR_NONE),
       write_count_histogram_(writer_.commit_interval(), path_) {
   DCHECK(!path_.empty());
 }
 
 bool JsonPrefStore::GetValue(const std::string& key,
                              const base::Value** result) const {
   DCHECK(CalledOnValidThread());
 
   base::Value* tmp = NULL;
@@ skipping 349 matching lines @@
   DCHECK_EQ(31, num_buckets);
 
   // The histogram below is an expansion of the UMA_HISTOGRAM_CUSTOM_COUNTS
   // macro adapted to allow for a dynamically suffixed histogram name.
   // Note: The factory creates and owns the histogram.
   base::HistogramBase* histogram = base::Histogram::FactoryGet(
       histogram_name, min_value, max_value, num_buckets,
       base::HistogramBase::kUmaTargetedHistogramFlag);
   return histogram;
 }